What is the directional flow of the globe valve? 

What is the directional flow of the globe valve? 

The opening and closing member (valve flap) is driven by the valve stem, along the axis of the valve seat (sealing surface) to do a linear lifting movement of the valve are called a globe valve.

Globe valve is generally driven by the drive (handwheel), valve stem, valve body, valve cover, valve flap (closing member) and packing device, and other major components. The handwheel is connected to the valve stem, and the valve flap is driven by the valve stem, so that the valve flap moves reciprocally in the direction of the valve seat axis, thus making the pipeline connected or cut off.

Shut-off valves have become one of the most commonly used valves in companies in almost every industry. With their ability to start, stop, and throttle fluid flow in a pipeline, it's easy to see why. But how do these valves actually work? What is the directional flow of a globe valve? 

 

Shut-off valve directional flow.

The most important thing to understand about globe valve directional flow is that they have a specific flow direction. Depending on the application, a globe valve will have fluid flow above or below the valve flap.

Shutoff valve directional flow is designed to allow pressure to flow below the valve flap in shutoff valves used in low-pressure and low-temperature applications such as general piping. This flow direction allows the valve flap to rotate freely on the valve stem. This allows the valve flap to fit properly against the seat when the valve is closed, thereby reducing seat leakage.

When used as part of high-pressure and high-temperature systems, globe valves can also create pressure flow over the valve seat. This flow direction helps prevent the valve stem from contracting as it cools and prevents the valve flap from lifting off the seat.

To determine the flow direction of a globe valve, simply look at its body. Here, you should find an arrow indicating the direction of flow of the valve.

 

Principle of operation of globe valves.

The globe valve stem generally makes a rotary lift motion with the handwheel fixed to the top of the stem. When the handwheel is rotated clockwise, the stem threads rotate down, the valve sealing surface and the valve seat sealing surface in close contact, and the shut-off valve to close state; when the handwheel is rotated counterclockwise, the stem threads rotate up, the valve sealing surface and the valve seat sealing surface disengage, the shut-off valve open.

 

Selection of globe valve.

Globe valve is one of the most widely used valves, although ball valves and butterfly valves continue to develop, in some cases can replace the globe valve, but the globe valve itself has some characteristics and can not be completely replaced by the ball valve, butterfly valve. The selection of globe valves should follow the following principles.

1, high temperature, high-pressure media on the pipeline or device should be used on the disconnecting valve. Such as thermal power plants, nuclear power plants, petrochemical systems, high-temperature, high-pressure pipeline selection of disconnecting valves is appropriate.

2, the flow resistance requirements are not strict on the pipeline, that is, the pressure loss is not a big consideration where you can give preference to disconnecting valves.

3, small valves can be used for globe valves, such as needle valves, instrumentation valves, sampling valves, pressure gauge valves, etc.

4, there are flow regulation or pressure regulation, but the requirements for regulation accuracy are not high, and the pipeline diameter is relatively small, such as the nominal size is not greater than DN50 on the pipeline, so it is appropriate to use the throttle type globe valve.

5, ammonia industry in the small fertilizer and fertilizer should be used for nominal pressure PN160 or PN320 high-pressure angular disconnecting valve or high-pressure angular throttle valve.

6, alumina Bayer production in the desilicon workshop, easy to coke on the pipeline, it is appropriate to use the valve body separate type, the seat can be replaced, carbide sealing sub-DC globe valve or DC throttle valve.

7, urban construction of water supply, heating projects, the nominal size of the pipeline, you can choose the globe valve, balancing valve, or plunger valve, such as the nominal size of less than DN150 pipeline.

8, large oxygen pipeline, due to the existence of other valves friction prone to static fire, so the use of large-diameter stainless steel disconnecting valve.

 

How to choose a globe valve?

The easiest way to choose the right globe valve is to consider the application conditions that require its use.

① Regulate the flow of basic systems operating with low temperature and low-pressure materials choose a globe valve designed to have pressure flow below the valve seat.

Those who need a valve to withstand more severe conditions should choose a globe valve that allows pressure to flow above the valve flap.

To learn more about globe valve flow and how to select the best value for your plant, contact WESDOM today.

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